Crystals of Benzamide, the First Polymorphous Molecular Compound, Are Helicoidal

Alexander G. Shtukenberg, Ran Drori, Elena V. Sturm, Netta Vidavsky, Asaf Haddad, Jason Zheng, Lara A. Estroff, Haim Weissman, Sharon G. Wolf, Eyal Shimoni, Chao Li, Noalle Fellah, Efi Efrati, Bart Kahr

Research output: Contribution to journalArticlepeer-review


The growth of spontaneously twisted crystals is a common but poorly understood phenomenon. An analysis of the formation of twisted crystals of a metastable benzamide polymorph (form II) crystallizing from highly supersaturated aqueous and ethanol solutions is given here. Benzamide, the first polymorphic molecular crystal reported (1832), would have been the first helicoidal crystal observed had the original authors undertaken an analysis by light microscopy. Polymorphism and twisting frequently concur as they are both associated with high thermodynamic driving forces for crystallization. Optical and electron microscopies as well as electron and powder X-ray diffraction reveal a complex lamellar structure of benzamide form II needle-like crystals. The internal stress produced by the overgrowth of lamellae is shown to be able to create a twist moment that is responsible for the observed non-classical morphologies.

Original languageEnglish (US)
Pages (from-to)14593-14601
Number of pages9
JournalAngewandte Chemie - International Edition
Issue number34
StatePublished - Aug 17 2020


  • benzamide
  • disorder
  • internal stress
  • polymorphism
  • twisted crystals

ASJC Scopus subject areas

  • Catalysis
  • General Chemistry


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